WEDNESDAY, Aug. 5, 2015 (HealthDay News) -- Older adults scoring poorly in higher-level thinking skills -- those used to reason, plan and solve problems -- are significantly more likely to suffer a heart attack or stroke, new research suggests.

European scientists found that seniors with the lowest scores of so-called "executive function" thinking skills were at an 85 percent higher risk of heart attack and 51 percent increased risk of stroke compared to those with the highest scores.

The study indicates heart and brain function are closely tied, said study author Dr. Behnam Sabayan, a post-doctoral research fellow at Leiden University Medical Center in the Netherlands.

"This might reflect that damage to [blood] vessels is a global phenomenon in our body and when we see abnormalities in one organ, we should think about the other organs as well," Sabayan said.

However, this study does not prove a cause-and-effect relationship between poor thinking skills and the incidence of heart attack and stroke, merely an association between the two.

"I think other factors can also play roles," Sabayan explained. For example, he suggested, people who have a slower thought process may find it more difficult to follow their doctors' advice.

The study is published in the Aug. 5 online edition of the journal Neurology.

Most heart attacks and strokes are triggered by clots in arteries, cutting off blood supply to portions of the heart or brain. Heart disease remains the top killer of Americans, while strokes kill one American every four minutes, according to the U.S. Centers for Disease Control and Prevention.

Sabayan and his colleagues looked at nearly 4,000 people with an average age of 75. None had a history of heart attacks or strokes. But, all of the study volunteers either had a history of heart disease or an increased risk due to high blood pressure, diabetes or smoking. None of the participants suffered from dementia, a brain condition marked by memory loss.

Participants took four tests of higher-level thinking skills indicating "executive function" -- such as reasoning, problem-solving or planning -- and were placed into groups of low-, medium- and high-scorers based on the results. They were then tracked for an average of three years to determine their prevalence of heart attacks or strokes.

In that time, 176 of 1,309 people with the lowest scores suffered heart attacks, compared with 93 of 1,308 people with the highest scores. Meanwhile, there were 69 strokes among those with the lowest scores compared with 48 strokes among those with highest scores, the study found.

While participants with lower executive function scores were slightly older on average and had fewer years of education, the results stood even after adjustment for these factors, Sabayan said.

"I believe when it comes to vascular events, control of cardiovascular risk factors such as [high blood pressure] or diabetes and healthy lifestyle are more important than innate intelligence," he said.

The study didn't find an association between lower memory scores and a higher risk of heart attack or stroke.

Dr. Gustavo Roman, a neurologist at Houston Methodist Hospital in Texas, praised the research, saying it reinforced his experience that patients with executive function problems often have blood vessel disease manifesting as heart attacks or strokes.

But Roman, who wasn't involved in the new study, noted that those with poor thinking skills may also make unwise decisions about diet, exercise and health care that can place them at higher risk for heart attack or stroke.

"That's certainly a possibility because executive function [is regulated by] the frontal lobes in general, which is sort of the command and control center of the brain," he said. "This part of the brain tells you how to achieve certain goals."

Patients with poor executive function don't follow directions well, Roman said, meaning "clinicians cannot take for granted the fact that whatever you tell these patients, they'll be able to comply."

Involved caregivers who can assist these patients in following doctors' suggestions about lifestyle and medication use can potentially help them lower their risks for heart attack and stroke, he said.